As the micro-grid operating in the grid and island conditions, the fault current gap is large, which making it difficult to identify and realize a better coordination between the upper and lower lines. In this paper, it is necessary to consider the requirements of the traditional protection setting and the difficulty of setting the upper and lower line tripping time of the microgrid in the two modes of operation. In this way, it is proposed to use the positive sequence current to identify the fault current direction and adopt the overcurrent coordination protection condition under the grid and island state protection. Secondly, this paper proposes an adaptive tuning delay and stepped backup delay based on the communication system to realize the upper and lower protection of the line as the selective scheme. For the more micro-radiation micro-network, the communication system to the public connection point for the most advanced, each line level in turn decline, which subordinate delay signal to the higher level transmission. In the MATLAB / Simulink environment, a typical example of radiation microgrid is constructed, and the effectiveness of the comprehensive protection scheme is verified by typical working conditions.